The Stabila 06250 LD250BT Laser Distance Measuring Tool with Bluetooth is a compact laser measurer that wirelessly transfers measurement data from laser to tablet or smartphone. This device provides quick measureing results needed on the building site and is able to make rapid measurements with easy to operate functions. Additional features include large figures and illuminated display provide good readability, impact-resistant housing and shock-absorbing STABILA soft grip casing. It is designed for measurements up to 50 meters and runs on 2 AAA Alkaline batteries (included). Specifications: Typical Measureing Accuracy: ± 2.0 mm Typical Measuring Distance: (0.2 – 50 m) Laser Wavelength: 635 m Bluetooth: Yes Free App: Yes Batteries Included: 2 x AAA Battery Life: Up to 5,000 measurements Output: Protection Class: IP54 Item Weight: 1 pound . It is a clas 2 laser with 0.95 mW